Microstructure-controlled copolymers of ethylene and C3-C10 alpha-olefins

ABSTRACT

A copolymer including ethylene units and units of one or more C 3-10  alpha-olefins. The copolymer has a number average molecular weight of less than 5,000 g/mol, as measured by GPC. The ethylene content of the copolymer is less than 80 mol %. At least 70% of molecules of the copolymer have an unsaturated group, and at least 70% of said unsaturated groups are located in a terminal vinylidene group or a tri-substituted isomer of a terminal vinylidene group. The copolymer has a crossover temperature of −20° C. or lower and/or a certain ethylene run length. Also disclosed are a method for making the copolymer and polyolefins plasticized with 1-40 wt % of the copolymer.

BACKGROUND OF THE INVENTION

The present invention relates to poly(alpha-olefin) plasticizers andplasticized polymers comprising such poly(alpha-olefin) plasticizers.

Polyolefins are used for making a wide variety of products. However, onedrawback of some polyolefins is their relatively high glass transitiontemperature (T_(g)). Polypropylene homopolymers and copolymers areparticularly problematic in this respect. This high T_(g) may result inmaterials that are difficult to process and which may be brittle,especially at low temperatures. Also, for many products, high molecularweight polyolefins are required to provide the desired polymerproperties. High molecular weight polyolefins can be even more difficultto process, due to their high melt viscosities.

As a result, there is a need to provide polymers with goodprocessability that are also able to maintain their advantageousproperties over time when exposed to a wide temperature range.

One important property for such polymers is low-temperature toughnesswhich should be improved while still providing a polymer that maintainsits properties upon exposure to elevated temperatures over time.

Addition of a plasticizer to a polyolefin is known to improve propertiessuch as impact strength and processability. Such plasticizers are oftenused to lower the T_(g) of the polymer. Lowering the T_(g) of thepolymer can improve the processability and low temperature impacttoughness of the polymer and reduce the tendency of the polymer tobecome brittle at low temperatures. In order to achieve this combinationof advantages, the plasticizer should have the ability to maintain itsviscosity at low temperature. Some plasticizers have a tendency tocrystallize or form structure in the plasticizer at low temperaturesleading to an undesirable increase in viscosity of the plasticizer. Thismay result in an adverse impact on the low temperature impact toughnessof a polymer plasticized with this plasticizer by causing the polymer tobecome brittle.

Many plasticized polymers also suffer from problems such as blooming ordiffusion of plasticizer to the surface of the polymer, or evenvolatilization of the plasticizer from the polymer, each resulting inlong-term deterioration of polymer properties. As a result, plasticizersare sought which have a relatively low pour point and thus can impartthe advantageous lowering of the T_(g) of the polymer discussed abovewhile at the same time ensuring that the polymer retains itsadvantageous properties over time, particularly when exposed to hightemperatures. In order to achieve this, the volatility or tendency ofthe plasticizer to diffuse to the surface of the polymer must bebalanced with the lowering of the Tg of the polymer. One way to reducethe volatility of the plasticizer is to increase its number averagemolecular weight. However, increasing the number average molecularweight can have an adverse influence on the Tg of the plasticizedpolymer and the processability of the polymer.

Plasticizers having lower number-average molecular weights (M_(n)) tendto be better at lowering the T_(g) of the polymer since the T_(g) of thepolymer tends to be inversely proportional to the M_(n) of theplasticizer. However, as the number-average molecular weight (M_(n)) ofthe plasticizer decreases, the plasticization durability of theproperties imparted by the plasticizer to the polymer is adverselyaffected, especially when exposed to high temperatures. This is at leastpartially due to the increased tendency of the plasticizer to migrate tothe surface of the polymer and/or volatilize. Thus, improvedplasticizers are sought that have the ability to lower the T_(g) of apolymer without lowering the number average molecular weight of theplasticizer.

Another key aspect for selection of an appropriate plasticizer is thechemical compatibility of the plasticizer with the polymer. To achievethis goal, it is desirable to employ plasticizers that are chemicallysimilar to the polymer that is being plasticized. This will enhance thechemical compatibility between the plasticizer and the polymer. For thispurpose, polyalphaolefins (PAOs) have been proposed for use aspolyolefin plasticizers.

Such PAOs are typically oligomers of olefins having five or more carbonatoms. In some cases, such oligomers with five or more carbon atoms maybe copolymerized with ethylene to C₄ olefins to reduce the pour point ofthe plasticizer. US 2004/054040 and WO 2004/014997 disclose PAOplasticizers having a weight average molecular weight (M_(w)) in therange of 100 to 20,000 g/mol. and a kinematic viscosity at 100° C.(KV₁₀₀) of 0.1 to 3,000 cSt.

US 2004/106723 and WO 2004/014998 disclose plasticizers having a KV₁₀₀of 10 cSt or more and a viscosity index (VI) of 100 or more. Theseplasticizers include oligomers of C₅ to C₁₄ olefins. U.S. Pat. No.4,536,537 discloses PAO plasticizers having a kinematic viscosity at 38°C. of about 2 to 6 cSt. WO 98/044041, WO 2002/018487 and WO 2003/048252disclose PAO plasticizers having a KV₁₀₀ of about 4 to 8 cSt.

WO 2009/020706 discloses plasticizers that are regularly branched PAOoligomers of one or more C₂-C₂₀ alpha-olefins having a KV₁₀₀ of 3 to3,000 cSt, a branching irregularity index (‘BII’) of 0.40 or less, and amolar-average carbon number (CLAO) of 6 to 14. Preferably, the regularlybranched PAOs have a Mw/Mn of less than 2.3. Polyolefins plasticizedwith the regularly branched PAOs are said to have a reduced volatilityas measured by thermogravimetric analysis, compared to comparablepolyolefin compositions plasticized with conventional PAOs, or a reducedglass transition temperature (Tg) of the composition compared tocomparable polyolefin compositions plasticized with conventional PAOs.

PAO plasticizers are typically prepared by olefin isomerization whichresults in oligomers having a variety of different structures caused by,for example, irregular branching. According to the present invention, ithas now been found that PAOs having certain characteristics indicativeof their structure can provide an improved combination of plasticizationefficiency and plasticization durability of the properties imparted bythe plasticizers when used in polyolefins.

BRIEF SUMMARY OF THE INVENTION

The present invention generally relates to copolymers that includeethylene units and units of one or more C₃₋₁₀ alpha-olefins, wherein thecopolymer has a number average molecular weight of less than 5,000 g/molas measured by GPC; the ethylene content of the copolymer is less than80 mol %; at least 70% of molecules of the copolymer have an unsaturatedgroup, and at least 70% of said unsaturated groups are located in aterminal vinylidene group or a tri-substituted isomer of a terminalvinylidene group; and the copolymer has a crossover temperature of −20°C. or lower.

The foregoing copolymer may have an average ethylene unit run length(n_(C2)) which is less than 2.8 or less than 2.6, as determined by ¹³CNMR spectroscopy, and also satisfies the relationship shown by theexpression below:

$n_{C\; 2} < \frac{\left( {{EEE} + {EEA} + {AEA}} \right)}{\left( {{AEA} + {0.5{EEA}}} \right)}$whereinEEE = (x_(C 2))³, EEA = 2(x_(C 2))²(1 − x_(C 2)), AEA = x_(C 2)(1 − x_(C 2))²,x_(C2) being the mole fraction of ethylene incorporated in the polymeras measured by ¹H-NMR spectroscopy, E representing an ethylene unit, andA representing an alpha-olefin unit.

The present invention also generally relates to copolymers that includeethylene units and units of one or more C₃₋₁₀ alpha-olefins, wherein thecopolymer has a number average molecular weight of less than 5,000 g/molas measured by GPC; the ethylene content of the copolymer is less than80 mol %; at least 70% of molecules of the copolymer have an unsaturatedgroup, and at least 70% of said unsaturated groups are located in aterminal vinylidene group or a tri-substituted isomer of a terminalvinylidene group; and the copolymer has an average ethylene unit runlength (n_(C2)) which is less than 2.8 or less than 2.6, as determinedby ¹³C NMR spectroscopy, and also satisfies the relationship shown bythe expression below:

$n_{C\; 2} < \frac{\left( {{EEE} + {EEA} + {AEA}} \right)}{\left( {{AEA} + {0.5{EEA}}} \right)}$whereinEEE = (x_(C 2))³, EEA = 2(x_(C 2))²(1 − x_(C 2)), AEA = x_(C 2)(1 − x_(C 2))²,x_(C2) being the mole fraction of ethylene incorporated in the polymeras measured by ¹H-NMR spectroscopy, E representing an ethylene unit, andA representing an alpha-olefin unit. This copolymer may have a crossovertemperature of −20° C. or lower.

In each of the foregoing embodiments, the ethylene content of thecopolymer may be less than 70 mol %, or less than 65 mol %, or less than60 mol %, or less than 55 mol %, or less than 50 mol %, or less than 45mol %, or less than 40 mol %. In each of the foregoing embodiments, theethylene content of the copolymer may be at least 10 mol % and less than80 mol %, or at least 20 mol % and less than 70 mol %, or at least 30mol % and less than 65 mol %, or at least 40 mol % and less than 60 mol%.

In each of the foregoing embodiments, the C₃-C₁₀ alpha-olefin content ofthe copolymer may be at least 20 mol %, or at least 30 mol %, or atleast 35 mol %, or at least 40 mol %, or at least 45 mol %, or at least50 mol %, or at least 55 mol %, or at least 60 mol %.

In each of the foregoing embodiments, at least 75 mol % of the copolymermay terminate in the terminal vinylidene group or the tri-substitutedisomer of the terminal vinylidene group, or at least 80 mol % of thecopolymer terminates in the terminal vinylidene group or thetri-substituted isomer of the terminal vinylidene group, or at least 85mol % of the copolymer terminates in the terminal vinylidene group orthe tri-substituted isomer of the terminal vinylidene group, or at least90 mol % of the copolymer terminates in the terminal vinylidene group orthe tri-substituted isomer of the terminal vinylidene group, or at least95 mol % of the copolymer terminates in the terminal vinylidene group orthe tri-substituted isomer of the terminal vinylidene group.

In each of the foregoing embodiments, the copolymer may have an averageethylene unit run length of less than 2.6, or less than 2.4, or lessthan 2.2, or less than 2.

In each of the foregoing embodiments, the crossover temperature of thecopolymer may be −25° C. or lower, or −30° C. or lower, or −35° C. orlower, or −40° C. or lower.

In each of the foregoing embodiments, the copolymer may have apolydispersity index of less than or equal to 4, or less than or equalto 3, or less than or equal to 2.

In each of the foregoing embodiments, the C₃-C₁₀ alpha-olefin units mayinclude propylene units.

In each of the foregoing embodiments, the number average molecularweight of the copolymer may be less than 4,000 g/mol, or less than 3,500g/mol, or less than 3,000 g/mol, or less than 2,500 g/mol, or less than2,000 g/mol, or less than 1,500 g/mol, or less than 1,000 g/mol. In eachof the foregoing embodiments, the number average molecular weight of thecopolymer may be between 800 and 3,000 g/mol.

In each of the foregoing embodiments, less than 20% of unit triads inthe copolymer are ethylene-ethylene-ethylene triads, or less than 10% ofunit triads in the copolymer are ethylene-ethylene-ethylene triads, orless than 5% of unit triads in the copolymer areethylene-ethylene-ethylene triads.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical representation of the comparison of averageethylene unit run length to purely Statistical and Alternatingmicrostructures at different ethylene incorporations for ethylene/C3copolymers, according to one or more embodiments;

FIG. 2 is a graphical representation of the effect of reactortemperature on microstructure, according to one or more embodiments;

FIG. 3 is a graphical representation of the crossover temperature versusaverage ethylene unit run length for worse than statistical and betterthan statistical microstructures, according to one or more embodiments;

FIG. 4 is a graphical representation of the crossover temperature versusaverage ethylene run length for only copolymers better than statisticalmicrostructures, according to one or more embodiments.

FIG. 5 is a graphical representation of the complex viscosity incentipoise (cP) measured by oscillatory rheometry versus temperature toshow the copolymer viscosity normalized by the 1H-NMR determined M_(n)and raised to the 3.4 power to remove the effect of molecular weight,comparing a 950 number average molecular weight highly reactive (HR)polyisobutylene, and a 2300 number average molecular weight HRpolyisobutylene to the product of Example 1 in accordance with thepresent invention.

FIG. 6 is a graphical representation of the dynamic viscosity incentipoise (cP) measured by rotational rheometry versus temperaturecomparing a 950 number average molecular weight HR polyisobutylene tothe product of Example 1 in accordance with the present invention.

FIG. 7 is a graphical representation of the complex viscosity incentipoise (cP) measured by oscillatory rheometry versus temperature toshow the copolymer viscosity normalized by the 1H-NMR determined M_(n)and raised to the 3.4 power to remove the effect of molecular weight,comparing the following materials 950 number average molecular weight HRpolyisobutylene, 2300 number average molecular weight HRpolyisobutylene, and a number of ethylene propylene copolymers.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention relates to ethylene-C₃-C₁₀ alpha-olefin copolymersand addition of such copolymers to one or more polyolefins in order toproduce a blend with improved properties as compared to the unmodifiedpolyolefin(s). Copolymers with certain characteristics may be employedto provide a better combination of properties in a plasticizedpolyolefin than conventional PAO plasticizers.

Various embodiments will now be described in greater detail below,including specific embodiments, versions and examples, but theinventions are not limited to these embodiments, versions or examples,which are included to enable a person having ordinary skill in the artto make and use the inventions, when the information in this patent iscombined with available information and technology.

Definitions

The following definitions are made for purposes of this invention andthe claims thereto.

When a polymer or copolymer is referred to as comprising an ethyleneunit or an olefin unit, the ethylene or olefin unit present in thepolymer or copolymer is the polymerized or oligomerized form of theethylene or olefin, respectively. The term, “polymer” is meant toencompass homopolymers and copolymers. The term, “copolymer” includesany polymer having two or more units from different monomers in the samechain, and encompasses random copolymers, statistical copolymers,interpolymers, and block copolymers. When a copolymer is said tocomprise a certain percentage of an ethylene or olefin unit, thatpercentage is based on the total amount of units in the copolymercomponents.

A “polyolefin” is a polymer comprising at least 50 mol % of one or moreolefin monomers. Preferably, a polyolefin comprises at least 60 mol %,or at least 70 mol %, or at least 80 mol %, or at least 90 mol %, or atleast 95 mol %, or 100 mol % of one or more olefin monomers. Preferably,the olefin monomers are selected from ethylene to ethylene₀ olefins, orethylene to C₁₆ olefins, or ethylene to C₁₀ olefins. More preferably theolefin monomers are selected from ethylene, propylene, 1-butene,1-hexene, and 1-octene. Polyolefins may also comprise up to 50 mol % ofone or more diene monomers.

The nomenclature “C_(x)” where x is an integer means there are “xcarbons” in the compound; for example, a “C₅ alpha-olefin” is analpha-olefin with 5 carbon atoms.

For purpose of this invention and the claims thereto, unless otherwisenoted, physical and chemical properties described herein are measuredusing the test methods described under the Experimental Methods section.

In one aspect, there is disclosed copolymers of ethylene and C₃-C₁₀alpha-olefins that are suitable for use as plasticizers, particular forplasticizing polyolefins.

Ethylene/Alpha-Olefin Copolymers

The copolymers described herein contain a plurality of ethylene unitsand a plurality of one or more C₃-C₁₀ alpha-olefin units. Exemplaryalpha-olefin units include propylene, butane, pentene, hexene, heptane,octene, nonene and decene units. Thus, the carbon number of eachalpha-olefin unit may be 3, 4, 5, 6, 7, 8, 9, or 10. The alpha-olefinunits may be derived from monomers such as, for example, propylene,1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or1-decene.

An ethylene unit generally refers to an —CH₂CH₂— unit within a copolymerchain. Ethylene units result from copolymerization of ethylene monomers.Alpha-olefin units generally refer to a unit such as the propylene unit—CH₂CH₂CH₂— and similarly result from copolymerization of alpha-olefinmonomers. The term “olefin” is given its ordinary meaning in the art,e.g., referring to a family of organic compounds which are alkeneshaving the chemical formula C_(x)H_(2x), where x is the carbon number,and wherein the alkenes have a double bond within their structure. Theterm “alpha-olefin” is given its ordinary meaning in the art and refersto olefins having a double bond within their structure at the primary oralpha position.

The Crossover Temperature

One important characteristic of the copolymer described herein is thecrossover temperature or onset temperature of the copolymer. Thecopolymer is generally viscoelastic; in other words, its mechanicalproperties are between those of a purely elastic solid and those of apurely viscous liquid. The viscoelastic behavior of the copolymer may becharacterized as the combination of an elastic portion (referred to aseither an elastic modulus or a storage modulus), and a viscous portion(referred to as either a viscous modulus or a loss modulus). The valuesof these moduli are used to characterize the viscoelastic properties ofthe copolymer at a given temperature. Both the storage modulus and theloss modulus are dependent on temperature, although each may change at adifferent rate as a function of temperature. Thus, the copolymer mayexhibit more elasticity or more viscosity, depending on the temperature.The crossover temperature is defined herein as the temperature at whichthe storage modulus equals the loss modulus. The crossover temperaturemay also be referred to as the onset temperature.

Oscillatory rheology is a technique that may be used to determine values(generally expressed in units of pressure) for the storage modulus andloss modulus. The basic principle of an oscillatory rheometer is toinduce a sinusoidal shear deformation in the sample (e.g., a sample ofcopolymer) and measure the resultant stress response. In a typicalexperiment, the sample is placed between two plates. While the top plateremains stationary, a motor rotates the bottom plate, thereby imposing atime dependent strain on the sample. Simultaneously, the time dependentstress is quantified by measuring the torque that the sample imposes onthe top plate.

Measuring this time dependent stress response reveals characteristicsabout the behavior of the material. If the material is an ideal elasticsolid, then the sample stress is proportional to the strain deformation,and the proportionality constant is the shear modulus of the material.In this case, the stress is always exactly in phase with the appliedsinusoidal strain deformation. In contrast, if the material is a purelyviscous fluid, the stress in the sample is proportional to the rate ofstrain deformation, where the proportionality constant is the viscosityof the fluid. In this case, the applied strain and the measured stressare out of phase.

Viscoelastic materials show a response that contains both in-phase andout-of-phase contributions. These contributions reveal the extents ofsolid-like and liquid-like behavior. A viscoelastic material will show aphase shift with respect to the applied strain deformation that liesbetween that of solids and liquids. These can be decoupled into anelastic component (the storage modulus) and a viscosity component (theloss modulus). The viscoelastic behavior of the system can thus becharacterized by the storage modulus and the loss modulus, whichrespectively characterize the solid-like and fluid-like contributions tothe measured stress response.

As mentioned above, the values of the storage modulus and loss modulusare temperature dependent. At warmer temperatures, the value of the lossmodulus for the copolymer is greater than the value of the storagemodulus. However, as the temperature decreases, the copolymer may behavemore like an elastic solid, and the degree of contribution from thestorage modulus approaches that from the loss modulus. As thetemperature lowers, eventually, at a certain temperature the storagemodulus of the copolymer crosses over the loss modulus and becomes thepredominant contributor to the viscoelastic behavior of the copolymer.According to one or more embodiments, a lower crossover temperature ofthe copolymer correlates to better low temperature performance of oilsinto which the copolymer is incorporated.

According to one or more embodiments, the copolymer may have a crossovertemperature of −20° C. or lower, −25° C. or lower, −30° C. or lower,−35° C. or lower, −40° C. or lower, −50° C. or lower, −60° C. or lower,or −70° C. or lower as determined by oscillatory rheometry. Other valuesare also possible. An advantageous crossover temperature for thecopolymer may be achieved through controlling characteristics of thecopolymer during its manufacture. One such characteristic is the averageethylene unit run length in the copolymer.

Average Ethylene Unit Run Length

According to one or more embodiments, the ethylene units and C₃-C₁₀alpha-olefin units within the copolymer may be arranged to provide goodlow temperature performance. On important characteristic of thearrangement of the ethylene and C₃-C₁₀ alpha-olefin units is the averageethylene unit run length. The average ethylene unit run length is anaverage of the number of ethylene units in each sequence of ethyleneunits in the copolymer. For example, in the sequence of units C₃-C₁₀alpha-olefin-ethylene-ethylene-C₃-C₁₀ alpha-olefin the ethylene unit runlength is two since there are two ethylene units in the run of ethyleneunits of this sequence. Thus, in a copolymer having the following twosequences (A) and (B), the ethylene unit run lengths are 2 and 3,respectively and the average ethylene unit run length is 2.5: (A) C₃-C₁₀alpha-olefin-ethylene-ethylene-C₃-C₁₀ alpha-olefin, and (B) C₃-C₁₀alpha-olefin-ethylene-ethylen-ethylene-C₃-C₁₀ alpha-olefin. In acopolymer molecule comprising a chain of ethylene and C₃-C₁₀alpha-olefin units, the units are not distributed uniformly within thecopolymer chain. The average ethylene unit run length may be determinedby dividing the total number of ethylene units by the number of ethyleneunit runs in the copolymer. For example, a copolymer having a total offour ethylene units and three runs of ethylene units has an averageethylene unit run length of 4/3=1.33.

Methods for determining values of the average ethylene unit run lengthare known in the art and comprise established spectroscopic proceduresusing ¹³C nuclear magnetic resonance methods as described, for example,in “Carbon-13 NMR in Polymer Science,” ACS Symposium Series 103,American Chemical Society, Washington, D.C. 1978 at p. 97 and in“Polymer Sequence Determination Carbon-13 NMR Method,” J. C. Randall,Academic Press, New York, N.Y. at p. 53.

Where the arrangement of the units in the copolymer chains is purelyrandom, each unit has a chance of appearing in a certain positionproportional to the remaining molar percentage of the monomercorresponding to that unit that is present in the monomer mixture,regardless of whether the immediately preceding unit is the same ordifferent. Thus, an expected average ethylene unit run length for apurely random unit distribution can be calculated as a function of themolar percentage of ethylene monomer. This value is referred to hereinas the statistically-expected random average ethylene unit run-length.

According to one or more embodiments, the copolymer may be synthesizedby a process through which the average run length of one of thecopolymer units is less than the statistically-expected random averageunit run length for a given molar percentage of the monomer of that unitpresent in the reaction mixture. For example, considering a copolymer ofethylene and propylene units, one or more catalysts and/or co-catalystsmay be chosen such that during copolymer chain formation, a propyleneunit is favored to bond to a preceding ethylene unit, while an ethyleneunit is favored to bond to a preceding propylene unit, as discussedfurther below. As a result of this choice, the average ethylene unit runlength in the copolymer can be reduced to be less than thestatistically-expected random average unit run length for the givenmolar percentage of ethylene monomers in the reaction mixture. Where theaverage run length is less than the statistically-expected randomaverage unit run-length, the copolymer is referred to as being between“statistical” and “alternating”, where “alternating” refers to acopolymer wherein the ethylene and propylene units always alternate.Alternatively, where the average unit run length is greater than thestatistically-expected random average unit run-length, the copolymer issaid to between “statistical” and “blocky.”

According to one or more embodiments, an average ethylene unit runlength in the copolymer is, at least in part, a function of thepercentage of ethylene units in the copolymer, and the chosencatalyst(s) and co-catalyst(s). For example, a higher percentage ofethylene units in the copolymer will result in a higher average ethyleneunit run length. The choice of catalyst and co-catalyst may be used toaffect the average ethylene unit run length, in situations where thecatalyst affects the relative insertion rate of insertion of thedifferent units of the copolymer.

During polymer chain formation, the reaction rate at which an ethylenemonomer bonds to a preceding ethylene unit at the end of the growingcopolymer chain is referred to as the ethylene-ethylene reaction rateconstant (“k_(pEE)”). The reaction rate at which a propylene (or otheralpha-olefin monomer) bonds to an ethylene unit at the end of thegrowing copolymer chain is referred to as the ethylene-propylenereaction rate constant (“k_(pEP)”). The reactivity ratio of ethylene(“r_(E)”) refers to the ratio of the ethylene-ethylene reaction rateconstant to the ethylene-propylene reaction rate constant,k_(pEE)/k_(pEP).

Likewise, the reaction rate at which a propylene (or other alpha-olefin)monomer bonds to a propylene unit at the end of the growing copolymerchain is referred to as the propylene-propylene reaction rate constant(“k_(pPP)”). The reaction rate at which an ethylene monomer bonds to apropylene unit at the end of the growing copolymer chain is referred toas the ethylene-propylene reaction rate constant (“k_(pPE)”). Thereactivity ratio of propylene (“r_(P)”) refers to the ratio of thepropylene-propylene reaction rate constant to the propylene-ethylenereaction rate constant, k_(pPP)/k_(pPE).

The lower each of the reactivity ratios (r_(E) or r_(P)) are, the morelikely it is that a different unit will follow the preceding unit andthus the resulting copolymer chain will tend to have an alternatingcharacter, with a lower average ethylene unit run length than thestatistically-expected random average ethylene unit run-length.According to one or more embodiments, selection of an appropriatecatalyst, as well as control of other process parameters, may reduce oneor more of the reactivity ratios for various units/monomers and maytherefore also reduce the average ethylene unit run length.

A lower average ethylene unit run length may provide certain advantages.For example, it may result in a lower crossover temperature for thecopolymer, thereby improving one or more aspects of performance such ascold-weather performance of a polyolefin plasticized with the copolymer.In general, the shorter the average ethylene unit run length, the lowerthe crossover temperature of the copolymer, which ultimately results ina better low temperature performance for polyolefins plasticized withthe copolymer.

According to one or more embodiments, a copolymer comprising ethyleneand C₃-C₁₀ alpha-olefin units is selected to have an average ethyleneunit run length that is less than the statistically-expected randomaverage ethylene unit run-length for the given molar percentage ofethylene units in the copolymer. The formulae (2)-(5) below can be usedto calculate the statistically-expected random average ethylene unitrun-length for the given molar percentage of ethylene units in thecopolymer. For example, as shown in FIG. 2, copolymerization in thepresence of a coordination polymerization catalyst comprising thecoordinated metallocene Cp₂ZrCl₂, and a methylaluminoxane co-catalyst,under certain conditions, results in the production of a copolymerhaving an average ethylene unit run length that is less than thestatistically expected run length for a random distribution at the givenmolar percentage of ethylene units in the copolymer.

According to one or more embodiments, the copolymer may have an averageethylene unit run length that is less than 3.0, less than 2.9, less than2.8, less than 2.7, less than 2.6, less than 2.5, less than 2.4, lessthan 2.3, less than 2.1, or less than 2.0. In such embodiments, theaverage ethylene unit run length may also be selected to be is less thanthe statistically-expected random average ethylene unit run-length forthe given molar percentage of ethylene units in the copolymer.

Statistical and Alternating Microstructures

Copolymers of ethylene and propylene produced with perfectly alternatingmicrostructures do not have a distribution of ethylene unit run lengths,as every sequence of ethylene units is exactly the same length. Theethylene unit run length for a perfectly alternating microstructure iscalculated from Equation (1).

$\begin{matrix}{n_{{C\; 2},{Alternating}} = \frac{x_{C\; 2}}{\left( {1 - x_{C\; 2}} \right)}} & (1)\end{matrix}$

Copolymers that do not have a perfectly alternating microstructure havea distribution of ethylene unit run lengths, and the prediction for apurely statistical microstructure of a copolymer represents the averageethylene unit run length for the distribution of ethylene unit runlengths in that copolymer. The average ethylene unit run length forcopolymers produced with a purely statistical microstructure can becalculated using Bernoullian statistics, as shown in Equation (2). Themole fraction of ethylene incorporated in the polymer, x_(ethylene), asmeasured by ¹H-NMR spectroscopy, is used to calculate the fraction ofEEE, EEP and PEP triads in the copolymer (there are also EPE, PPE andPPP triads) in a purely statistical polymer using Equations (3)-(5)given below.

$\begin{matrix}{n_{{C\; 2},{Statistical}} = \frac{\left( {{EEE} + {EEP} + {PEP}} \right)}{\left( {{PEP} + {0.5{EEP}}} \right)}} & (2) \\{{EEE} = \left( x_{C\; 2} \right)^{3}} & (3) \\{{EEP} = {2\left( x_{C\; 2} \right)^{2}\left( {1 - x_{C\; 2}} \right)}} & (4) \\{{PEP} = {x_{C\; 2}\left( {1 - x_{C\; 2}} \right)}^{2}} & (5)\end{matrix}$E represents an ethylene unit and P represents a propylene unit and thusthe triad “EPE” represents the three unit triadethylene-propylene-ethylene.

The experimental ethylene incorporation in mol % was determined by¹H-NMR using a standard technique known to those of ordinary skill inthe art. The experimental average ethylene unit run length wasdetermined by ¹³C-NMR using the standard technique discussed above. Acomparison of the experimentally determined average ethylene unit runlength and the calculations for the alternating and statistical resultsare shown in FIG. 1 at different molar percentages of ethyleneincorporation. A comparison of the experimental results for ethyleneunit run length to the calculated statistical and alternating resultsyields an indication of whether the copolymers have microstructures thatare worse or better than statistical. It is believed thatmicrostructures that are worse than statistical have a broaderdistribution of ethylene unit run lengths about the average ethyleneunit run length. Such microstructures have some ethylene unit runlengths that are worse than the average and some that are better thanthe average.

Increasing the ethylene content of the copolymer increases theplasticization efficiency, plasticization durability, and oxidativestability of the plasticizer but also decreases the amount of structureforming that may occur at lower temperatures. It is unexpected that theparticular combination of properties and microstructure of the copolymerof the present invention provides adequate plasticization efficiency,plasticization durability, and oxidative stability while at the sametime providing a good low temperature performance.

The results shown in FIG. 1 were produced with two different catalystsystems. The ethylene incorporation was controlled during thepolymerization using standard techniques known in the art. Thecopolymerization using the Cp₂ZrCl₂/MAO catalyst system was carried outat a lower temperature and within a narrower temperature range than thecopolymerization using the Cp₂ZrMe₂/FAB/TEAL catalyst system, shown inFIG. 2.

The copolymerization reaction can be controlled to provide the desiredcopolymers of the invention. Parameters such as the reactiontemperature, pressure, mixing, reactor heat management, feed rates ofone or more of the reactants, types, ratio, and concentration ofcatalyst and/or co-catalyst and/or scavenger as well as the phase of thefeed components can be controlled to influence the structure of thecopolymer obtained from the reaction. Thus, a combination of severaldifferent reaction conditions can be controlled to produce the desiredcopolymer.

For example, it is important to run the copolymerization reaction withappropriate heat management. Since the copolymerization reaction isexothermic, in order to maintain a desired set point temperature in thereactor heat must be removed. This can be accomplished by, for example,two different methods often practiced in combination. Heat can beremoved by cooling the feed stream to the reactor to a temperature wellbelow the reaction set point temperature (even sometimes cryogenically)and therefore allowing the feed stream to absorb some of the heat ofreaction through a temperature rise. In addition, heat can be removedfrom the reactor by external cooling, such as a cooling coil and/or acooling jacket. The lower the set point temperature in the reactor, themore demand there is for heat removal. The higher the reactiontemperature, the less heat needs to be removed, or alternatively or incombination, the more concentrated the copolymer can be (higherproductivity) and/or the shorter the residence time can be (smallerreactor). The results characterizing the deviation of the averageethylene unit run length from a purely statistical microstructure areshown in FIG. 2 for both catalyst systems plotted versus the temperatureof the reactor during the copolymerization.

As the reaction temperature was increased beyond 135° C., it appearsthat control of the microstructure may be lost and the copolymertypically becomes worse than statistical. As a result, the lowtemperature properties of the copolymer may be compromised. Withoutbeing bound by theory, the reduced control of the microstructure ofcopolymers produced at higher temperatures is believed to be due to adrop in the reaction kinetics of comonomer incorporation relative toethylene incorporation. The more difficult it is for the comonomer toincorporate in the copolymer, the less regularly the comonomer breaks upthe runs of ethylene units in the chain during copolymerization. Somestrategies for improving the incorporation of comonomer at higherreaction temperatures include increasing the ratio of monomers of C₃-C₁₀alpha-olefin/ethylene in the reactor, increasing the Al/Zr ratio in thecatalyst or by making changes in the catalyst architecture.

Thus, in some embodiments of the invention, reaction temperatures of60-135° C. are employed for the copolymerization reaction, or, morepreferably, reaction temperatures of 62-130° C., or 65-125° C., orpreferably 68-120° C. or 70-90° C., are employed for thecopolymerization reaction.

A preferred Al/Zr ratio in the catalyst system may be less than10,000:1, less than 1,000:1, less than 100:1, less than 10:1, less than5:1, or less than 1:1. For boron-containing technology, a preferredAl/Zr ratio in the catalyst is less than 100:1, less than 50:1, lessthan 10:1, less than 5:1, less than 1:1, less than 0.1:1 and a preferredB/Zr ratio is less than 10:1, less than 5:1, less than 2:1, less than1.5:1, less than 1.2:1, or less than 1:1.

Low temperature properties of the copolymer can be correlated to themicrostructure of the copolymer. Low temperature performance of the purecopolymer is measured by Oscillatory Rheometry. The point at whichstorage modulus is equal to the loss modulus, the crossover or onsettemperature, is an indication of the temperature at which the copolymerwill begin to exhibit unfavorable structure forming. The crossovertemperature is the point at which the structure formed in the polymerexceeds the liquid-like character of the polymer. This temperature hasbeen shown to be predictive for determining the impact of the copolymerstructure on low temperature performance as a polyolefin plasticizer.

The impact of average ethylene unit run length on crossover temperatureis shown in FIGS. 3 and 4. The copolymers produced with the Cp₂ZrCl₂/MAOcatalyst system are well-behaved and there is a strong correlationbetween crossover temperature and average ethylene unit run length. Thecopolymers produced with the Cp₂ZrMe₂/FAB/TEAL catalyst system can becontrolled to provide the desired combination crossover temperature andaverage ethylene unit run length. A particularly wide range of crossovertemperatures is observed for the copolymers produced using theCp₂ZrMe₂/FAB/TEAL catalyst system is shown in FIG. 3. Specifically, atan approximate ethylene unit run length of 2.6, the crossovertemperature of these copolymers varies from almost −40° C. to about 5°C. This wide range in crossover temperature correlates with the widevariety of different microstructures that was also observed for thesecopolymers at the same average ethylene unit run length.

Triad Distribution

In some embodiments, the sequential arrangement of units in thecopolymer may, alternatively, be described with reference to the triaddistribution. The triad distribution refers to the statisticaldistribution of the possible combinations of three units in a row in thecopolymer chain. Taking as an example an ethylene-propylene copolymer,where “E” represents an ethylene unit and “P” represents apropylene-derived unit, the potential combinations of unit triads are:EEE, EEP, PEP, EPE, PPE, and PPP. According to one or more embodiments,the percentage of EEE units based on the total number of unit triads inthe copolymer is preferably less than 20%, less than 10%, or less than5%. The percentage of EEE units is indicative of a relatively shortaverage ethylene unit run length in such copolymers.

The method used for calculating the triad distribution ofethylene-propylene copolymers is described in J. C. Randall JMS-ReviewMacromolecules Chem Physics ethylene 9, 201 (1989) and E. W. Hansen, K.Redford Polymer Vol. 37, No. 1, 19-24 (1996). After collecting ¹³C(¹H)NMR data under quantitative conditions, eight regions (A-H), shown inTable 1 are integrated. The equations of Table 2 are applied and thevalues normalized. For the examples described herein, the D, E, and Fregions were combined due to peak overlap in the NMR spectra. The symbol“k” represents a normalization constant and T=the total intensity.

TABLE 1 Integral Regions Chemical Shift Region (ppm) A 43.5-48.0 B36.5-39.5 C 32.5-33.5 D 29.2-31.2 E 28.5-29.3 F 26.5-27.8 G 23.5-25.5 H19.5-22.5

TABLE 2 Equations k(EEE) = 0.5(T_(DEF) + T_(A) + T_(C) + 3T_(G) − T_(B)− 2T_(H)) K(PEE + EEP) = 0.5(T_(H) + 0.5T_(B) − T_(A) − 2T_(G)) k(PEP) =T_(G) k(EPE) = T_(C) k(EPP + PPE) = 0.5(2T_(H) + T_(B) − 2T_(A) −4T_(C)) k(PPP) = 0.5(3T_(A) + 2T_(C) − 0.5T_(B) − T_(H))Molecular Weight

The number average molecular weight of the copolymer can be determinedby ¹H-NMR or gel permeation chromatography (GPC), as described in U.S.Pat. No. 5,266,223, with the GPC method being preferred. The GPC methodadditionally provides molecular weight distribution information; see W.W. Yau, J. J. Kirkland and D. D. Bly, “Modern Size Exclusion LiquidChromatography”, John Wiley and Sons, New York, 1979. According to someembodiments, the copolymer may have a number average molecular weight ofless than 5,000 g/mol, of less than 4,500 g/mol, of less than 4,000g/mol, of less than 3,500 g/mol, of less than 3,000 g/mol, of less than2,800 g/mol, of less than 2,500 g/mol, of less than 2,000 g/mol, of lessthan 1,500 g/mol, or of less than 1,000 g/mol as determined by GPC.According to some embodiments, the copolymer may have a number averagemolecular weight of greater than 200 g/mol, 500 g/mol, of greater than800 g/mol, of greater than 1,000 g/mol, as determined by GPC.Combinations of all of the above-referenced end points to form rangesare also possible and are disclosed herein. Other values are alsopossible.

The polydispersity index (PDI) of the copolymer is a measure of thevariation in the length, in units, of the individual chains of thecopolymer. The polydispersity index is determined by dividing the weightaverage molecular weight (M_(w)) of the copolymer by the number averagemolecular weight (M_(n)) of the copolymer. The term number averagemolecular weight (determined by, e.g., ¹H-NMR or GPC) is given itsordinary meaning in the art and is defined as the sum of the products ofthe weight of each polymer chain and the number of polymer chains havingthat weight, divided by the total number of polymer chains. The weightaverage molecular weight of the copolymer is given its ordinary meaningin the art and is defined as the sum of the products of the weightsquared of each polymer chain and the total number of polymer chainshaving that weight, divided by the sum of the products of the weight ofeach polymer chain and the number of polymer chains having that weight.According to one or more embodiments, the PDI of the copolymer(M_(w)/M_(n)) may be less than or equal to 4, less than or equal to 3,less than or equal to 2, or less than or equal to 1.

In some embodiments, it is desirable to provide copolymers that have alower kinematic viscosity without reducing the molecular weight of thecopolymer. This goal can be achieved in certain embodiments bycontrolling the microstructure of the copolymer as discussed above.

Viscosity and Complex Viscosity

One goal of embodiments herein is the provision of a copolymer with alower viscosity and higher molecular than a comparable copolymer. Forexample, referring to FIG. 6, there is shown a comparison of theviscosity versus temperature of a 950 number average molecular weightpolyisobutylene (TPC595) to a 1053 number average molecular weightcopolymer of 49 mol % ethylene and 51 mol % propylene (EP-4951-1053) inaccordance with the present invention. FIG. 6 shows that the viscosityof the copolymer of the present invention is significantly lower thanthe viscosity of polyisobutylene at all relevant temperatures eventhough the copolymer of the present invention has a higher molecularweight than the polyisobutylene. In this manner, improved plasticizationcan be achieved while also obtaining the advantage of a higher molecularweight which will tend to reduce diffusion of the copolymer to thesurface of a polyolefin polymer and/or inhibit volatilization of thecopolymer from the polyolefin.

FIG. 6 can be compared to FIG. 5 to see that for good copolymers withpoor microstructures, the complex viscosity is essentially the same asthe dynamic viscosity. However, if Mn is high enough (e.g. greater than3 times the entanglement (Me) for the polymer), the complex viscositywill vary from the dynamic viscosity. Examples of this variation due toentanglement can be seen in FIG. 7 where certain comparative copolymersexhibited erratic complex viscosities as the temperature decreased.

FIG. 7 is a graphical representation of the complex viscosity incentipoise (cP) measured by oscillatory rheometry versus temperature toshow the copolymer viscosity normalized by the 1H-NMR determined M_(n)and raised to the 3.4 power to remove the effect of molecular weight.This data shows that for ranges of temperature where poor copolymermicrostructure has little or no impact on the complex viscosity, thereis a clear distinction between the copolymers of the invention andpolyisobutylene, as also shown in FIGS. 5-6. When poor microstructurebegins to impact the complex viscosity, a clear deviation occursindicative of structure formation in the copolymer, as shown by thecomparative ethylene-propylene copolymers which had poor microstructure.As a result, these copolymers with poor microstructure will not be asbeneficial for plasticization in this range of temperatures wheremicrostructure plays an important role since structure forming in suchcopolymers will lead to an undesirable viscosity increase.

Ethylene Content

The copolymer may comprise a certain mole percentage (mol %) of ethyleneor ethylene units. According to some embodiments, the molar percentageof ethylene in the copolymer, is at least 10 mol %, at least 20 mol %,at least 30 mol %, at least 40 mol %, at least 45 mol %, at least 50 mol%, at least 55 mol %, at least 60 mol %, at least 65 mol %, at least 70mol %, or at least 75 mol %. According to some embodiments, the molarpercentage of ethylene units in the copolymer is less than 80 mol %,less than 75 mol %, less than 70 mol %, less than 65 mol %, less than 60mol %, less than 55 mol %, less than 50 mol %, less than 45 mol %, lessthan 40 mol %, less than 30 mol %, or less than 20 mol %, Combinationsof each of the above-mentioned end points to form ranges are alsopossible and are disclosed herein. Other ranges are also possible.

C₃-C₁₀ Alpha Olefin Comonomer Content

The copolymer may comprise a certain mole percentage of C₃-C₁₀alpha-olefin units. According to some embodiments, the molar percentageof the C₃-C₁₀ alpha-olefin units the copolymer, relative to the totalunits within the copolymer, is at least 20 mol %, at least 25 mol %, atleast 30 mol %, at least 35 mol %, at least 40 mol %, at least 45 mol %,at least 50 mol %, at least 55 mol %, at least 60 mol %, at least 65 mol%, at least 70 mol %, or at least 80 mol %. According to someembodiments, the C₃-C₁₀ alpha-olefin content of the copolymer is lessthan 90 mol %, less than 80 mol %, less than 70 mol %, less than 65 mol%, less than 60 mol %, less than 55 mol %, less than 50 mol %, less than45 mol %, less than 40 mol %, less than 35 mol %, less than 30 mol %,less than 25 mol %, or less than 20 mol %, less than 90 mol %.Combinations of any the above referenced limits can be made to formranges and are possible and disclosed herein. Other ranges are alsopossible.

Unsaturation

In many applications for plasticizers known in the art, it may bedesirable to provide a polymerizable plasticizer, a functionalizableplasticizer or a reactive plasticizer. For one or more of thesepurposes, it is desirable to include unsaturation in the copolymers ofthe present invention.

In the embodiments of the invention, the copolymer comprises a pluralityof copolymer molecules, at least 70% of which copolymer moleculescontain terminal unsaturation, i.e., a carbon-carbon double bond in theterminal unit of the copolymer. According to some embodiments, more than75%, more than 80%, more than 85%, more than 90%, more than 95%, or morethan 97%, of the copolymer molecules contain terminal unsaturation. Thepercentage of polymeric chains exhibiting terminal unsaturation may bedetermined by FTIR spectroscopic analysis, titration, or ¹³C NMR. See,e.g., U.S. Pat. No. 5,128,056.

End Groups

In the embodiments of the invention, the copolymer may terminate, at oneend, with either an ethylene unit or a C₃-C₁₀ alpha-olefin unit. Theterminal unsaturation mentioned above is located within a terminal groupof the copolymer molecule. If the terminal group containing the terminalunsaturation is an ethylene unit, the terminal unsaturation is presentin either a vinyl group or a di-substituted isomer of a vinyl group. Ifthe terminal group containing the terminal unsaturation is a C₃-C₁₀alpha-olefin unit, the terminal unsaturation is present in either avinylidene group or a tri-substituted isomer of a vinylidene group.

In some embodiments, more than 70%, more than 75%, more than 80%, morethan 85%, more than 90%, or more than 95% of the terminal unsaturationis located within a C₃-C₁₀ alpha-olefin terminal unit. In such case, theterminal group has one or more of the following structural formulas(I)-(III):

For each of Formulas (I)-(III), R represents the appropriate alkyl groupfor that particular C₃-C₁₀ alpha-olefin unit, e.g., a methyl group ifthe alpha olefin is propylene, an ethyl group if the alpha olefin is1-butene, etc., and

indicates the bond that is the point of attachment of the group (I),(II) or (III) to the remaining portion of the copolymer molecule.

As used herein, the terms “terminal vinylidene” and “terminal vinylidenegroup” refer to the structure represented by Formula (I). As usedherein, the terms “tri-substituted isomer of terminal vinylidene” and“tri-substituted isomer of terminal vinylidene group” refer to one ofthe structures represented by the Formulas (II) and (III).

Terminal vinylidene, tri-substituted isomers of terminal vinylidene, aswell as other types of terminal unsaturation in the copolymers can bedetected by ¹H-NMR. From the integrated intensity of each signal, theamount of each terminal group can be determined as discussed in US2016/0257862.

Chemical Compatibility

There are many tests that can be used to evaluate the chemicalcompatibility of thermoplastic materials. Three major groups of testsfor chemical compatibility include retention of physical/mechanicalproperties, visual evaluations and creep and creep rupture. Physicalproperties such as change in volume, weight, dimensions, or hardness areparticularly useful when evaluating chemical compatibility. Testsmonitoring the change in weight or hardness would be a good indicationof chemical compatibility. Plasticization allows movement of theindividual molecular chains causing the polymer to become increasinglyflexible as more plasticizer is absorbed. As in the case with solvation,change in weight, hardness, and in addition, dimension and volume aregood indicators of chemical compatibility.

Mechanical properties such as tensile strength and elongation, impact,and flexural strength can be very good indicators of chemicalcompatibility. In this type of testing the properties are performedinitially and again after time has elapsed. Plasticization tends tosoften polymers, increasing the ductility and thus causing an increasein the tensile elongation while at the same time lowering tensilestrength. The changes that occur are dependent on the amount ofplasticizer present and thus results can be affected by other factors.Chemical compatibility effects that can be difficult to determine byother methods such as Environmental Stress Cracking (ESC) can beestablished by testing retention of tensile properties.

Visual evaluations can be used in conjunction with almost any testmethod when determining chemical compatibility. One such test method isASTM D543, which combines visual evaluations with other tests. Thereare, however, test methods where visual evaluations and ratings are theprimary result. ASTM D1693, is designed for use with ethylene typeplastics and involves bending test specimens in a fixture, nicking thespecimens to initiate a controlled imperfection, and optionally applyingchemical agents. The specimens are then evaluated for crack growth andresults determined based on the number and severity of the cracks. ASTMD1 693 is limited to flexible materials, primarily opaque, and to theobservance of cracking.

Polymers can exhibit elastic deformation and reduction in strength whensolvation/plasticization occurs. Creep measurements are therefore usefulin determining compatibility with solvents or plasticizers. ASTM D2990is a suitable test for creep measurements.

Estimation of the solubility parameter is another suitable way todetermine chemical compatibility. The solubility parameter and molarvolume of each monomer can be estimated from the structure of themonomer. Specifically, the estimation method of Fedors, R. F., “A Methodfor Estimating Both the Solubility Parameters and Molar Volumes ofLiquids,” Pol. Eng. Sci., 14, 147-154 (1974) is employed for thecopolymers of the present application. This method employs the formula:

$\delta_{t} = \left( \frac{\sum{\Delta\; e_{i}}}{\sum{\Delta\; v_{i}}} \right)^{1\text{/}2}$wherein the group contributions are as given in Table 3 below.

TABLE 3 Group Contributions Group Δe_(i)/cal mol⁻¹ Δv_(i)/cm³ mol⁻¹ CH3—1120 33.5 CH2— 1180 16.1 CH— 820 −1.0

The group contributions shown in Table 3 are added for each monomer unitto obtain the total for each copolymer. For copolymers, the followingequation of Schneier. B., “An Equation for Calculating the SolubilityParameter of Random Copolymers,” Pol. Lett., 10, 245-251 (1972) can beused.

$\delta_{x} = \frac{{\delta_{1}V_{1}X_{1}} + {\delta_{2}V_{2}X_{2}}}{\left\lbrack {\left( {{V_{1}X_{1}} + {V_{2}X_{2}}} \right)V_{x}} \right\rbrack^{\frac{1}{2}}}$wherein 1, 2, and x are monomer 1, monomer 2, and the mixture,respectively, V is the molar volume, δ is the solubility parameter, andX is the mole weight fraction. The mole weight fraction is:

$X_{i} = \frac{n_{i}M_{i}}{{n_{1}M_{1}} + {n_{2}M_{2}}}$where M is the monomer molecular weight and n is the number of moles ofeach monomer. V_(x) is taken as the molar average of the two monomermolar volumes:

$V_{x} = \frac{{n_{1}V_{1}} + {n_{2}V_{2}}}{n_{1} + n_{2}}$wherein the total solubility parameters are as given in Table 4 below.

TABLE 4 Comparison of Total Solubility Parameters Polymerδ_(t)/MPa^(1/2) δ_(t)/(cal cm⁻³)^(1/2) poly(ethylene) 17.5 8.6poly(propylene) 16.4 8.0 poly(1-hexene) 17.0 8.3 poly(ethylenepropylene) 17.1 8.4 52 mole % ethylene poly(ethylene 1-hexene) 19.3 9.490 mole % ethylene

In some embodiments the plasticizer has a difference of no more than 2(cal cm⁻³)^(1/2) in the solubility parameter as compared to thesolubility parameter of the polyolefin or other polymer into which theplasticizer is to be incorporated. Another way to calculate thesolubility parameter for homopolymers is described in Small, P. A.,“Some Factors Affecting the Solubility of Polymers,” J. Appl. Chem., 3,71-79 (1953).

Various properties of the plasticizers of the present invention can bedetermined and/or evaluated based on the information given in,“Principles of Plasticization,” Immergut, E. H. and Mark, H. P., (1965),doi: 10.1021/ba-1965-0048.ch001, the disclosure of which is incorporatedby reference herein in its entirety for providing information fordetermining and evaluating properties of plasticizers.

Methods of Production of the Copolymers

A suitable method for the production of the copolymers of the inventionincludes a step of reacting ethylene and at least one C₃-C₁₀alpha-olefin using a coordination polymerization catalyst and aco-catalyst at a temperature of from 60° C. to 135° C. for a timesufficient to produce a copolymer comprising ethylene units and C₃-C₁₀alpha-olefin units. The reaction conditions are preferably controlledsuch that copolymer has a number average molecular weight of less than5,000 g/mol; at least 70 mol % of the copolymer terminates in a terminalvinylidene group or a tri-substituted isomer of a terminal vinylidenegroup; the copolymer has an average ethylene unit run length of lessthan 4, as determined through NMR spectroscopy; the copolymer has anethylene content of less than 80 mol %; and the copolymer has acrossover temperature of −20° C. or lower.

A metallocene comprises cyclopentadienyl anions (“Cp”) bound to a metalcenter. The C₃-C₁₀ alpha-olefin content can be controlled through theselection of the metallocene catalyst component and by controlling thepartial pressure or relative feed rates of the various monomers.

The metallocene catalysts employed in the production of the reactantpolymers are organometallic coordination compounds which arecyclopentadienyl derivatives of a Group 4b metal of the Periodic Tableof the Elements (56th Edition of Handbook of Chemistry and Physics, CRCPress [1975]) and include mono, di and tricyclopentadienyls and theirderivatives of the transition metals. Particularly desirable are themetallocene of a Group 4b metal such as titanium, zirconium, andhafnium. The aluminoxanes employed in forming the reaction product withthe metallocenes are themselves the reaction products of an aluminumtrialkyl with water.

In certain embodiments, the coordinated metallocene may comprise azirconium. For example, the coordinated metallocene may compriseCp₂ZrCl₂. In addition, a co-catalyst may optionally be employed. Theco-catalyst may comprise an aluminoxane such as methylaluminoxane.

The copolymer may be produced in a reactor. Parameters that may becontrolled during the copolymerization reaction include at leastpressure and temperature. The reaction may be operated continuously,semi-continuously, or batchwise. The ethylene may be delivered to thereactor as ethylene gas through a metered feed. The C₃-C₁₀ alpha-olefinmay be delivered to the reactor through a separate metered feed. Thecatalyst and optional co-catalyst may be delivered to the reactor insolution. The weight percentage of either the catalyst or theco-catalyst in the solution delivered to the reactor may be less than 20wt %, less than 15 wt %, less than 10 wt %, less than 8 wt %, less than6 wt %, less than 5 wt %, less than 4 wt %, less than 3 wt %, less than2 wt %, or less than 1 wt %, according to different embodiments. Theethylene, C₃-C₁₀ alpha-olefin, solvent and catalyst and optionalco-catalyst may then be mixed in the reactor. Skilled persons arefamiliar with many suitable reactions, reactors and reaction conditionsfor copolymerization of ethylene and C₃-C₁₀ alpha-olefins. Examples ofseveral processes for forming the copolymer are described in theexamples below.

The catalyst may comprise a granular support based especially on arefractory oxide such as, for example, silica and/or alumina. Such acatalyst can be prepared by a method comprising bringing the granularsupport into contact with (a) a dialkylmagnesium and optionally atrialkylaluminium, (b) a halogenated hydrocarbon e.g. a monohalogenatedhydrocarbon, (c) and a tetravalent titanium compound. Such a method isdescribed in European Patent Application EP-A-453,088.

The catalyst may also contain a magnesium chloride support and inparticular a preactived support such as that described in EuropeanPatent Application EP-A-336,545. A catalyst of this type can be preparedby a method comprising bringing a magnesium chloride support intocontact with (a) an organometallic compound which is a reducing agentfor titanium, (b) a tetravalent titanium compound and c) optionally oneor more electron-donor compounds. Such a method is described in FrenchPatent Application FR-A-2,669,640.

The catalyst may be used in the form of a solid as it is or in the formof a prepolymer, especially when it is used in a gas phasepolymerization. The prepolymer is obtained by bringing the catalyst intocontact with one or more of olefins e.g. containing from 2 to 8 carbonatoms such as, for example, ethylene or a mixture of ethylene with C₃-C₈olefin(s) in the presence of an organometallic cocatalyst. In general,the prepolymer obtained contains from 0.1 to 200 g preferably from 10 to100 g of polymer per millimole of titanium.

The catalyst may be employed with an organometallic cocatalyst which maybe chosen from organoaluminium, organomagnesium and organozinccompounds. In most cases the organometallic cocatalyst is analkylaluminium such as, for example, trimethylaluminium,triethylaluminium, tri-n-octylaluminium or else a mixture of thesecompounds.

The copolymers can alternatively be polymerized using catalysts preparedby the admixture of certain boron compounds with a salt of a metalselected from Groups 4a, 5a, 6a and 8, of the Mendeleeff Periodic Table.These compounds of boron are the hydrides and hydrocarbon derivatives ofboron. The boron hydride used in preparing such catalytic compositionsis usually diborane (B H although other hydrides of boron can also beused including, for example, pentaborane, hexaborane, and decaborane.

Hydrocarbon derivatives of boron which may be used include alkyl borons,cycloalkyl borons, aryl borons and the like. Examples of alkyl boronswhich can be used include, trimethyl boron, triethylboron, tripropylboron, tributyl boron, tridecyl boron and the like. Examples of arylborons include triphenyl boron, tritolyl boron, tri-p-xylyl boron,trinaphthyl boron and the like. Mixed hydride-hydrocarbon derivatives ofboron can also be used, e. g. symmetrical or asymmetricaldimethyldiborane, methyldiborane and the like. Also thehydrocarbon-halogen derivatives of boron, e. g. dimethylboron bromide,dimethylboron iodide, diphenylboron bromide or chloride, etc can beused. Exemplary boron catalysts can be found in, for example, U.S. Pat.Nos. 3,166,536; 3,160,672 and 2,840,551.

In some embodiments, the microstructure of the copolymer may bedesirably influenced by spatially distributing the composition uniformlywithin the reactor. Methods of ensuring uniformity of the spatialdistribution include, but are not limited to, agitation, selection ofparticular feed locations for feeding the monomers, solvent and catalystcomponents and particular methods of introducing one or more of thevarious components. Additional factors that may impact compositionaluniformity in the reactor include operation within a particulartemperature and/or pressure range that provides a single fluid phasewithin the reactor. In some embodiments this may involve ensuring thatthe reactor temperature and pressure conditions remain above the entirevapor-liquid phase behavior envelope of the feed composition. It is alsoenvisioned that premixing of two or more of the feed components may beemployed and the premixing time and mixing intensity of the feedcomponents may be useful for control of spatial uniformity within thereactor, at least in some cases. In certain embodiments it may also bedesirable to ensure that no pockets of vapor exist within the reactorthat would create a composition gradient either at a vapor-liquidinterface or within the liquid.

Some strategies for improving the incorporation of comonomer at higherreaction temperatures include increasing the ratio of monomers of C₃-C₁₀alpha-olefin/ethylene in the reactor, increasing the Al/Zr ratio in azirconium-containing coordination metallocene catalyst or by makingchanges in the catalyst architecture.

Temperature control may be used to influence the reactivity ratios in amanner that leads to microstructures with better than statisticalmicrostructures and/or to microstructures tending toward alternatingmicrostructures. Typically, lower temperature are advantageous forachieving a better than statistical microstructure and/or amicrostructure that tends toward alternation of the ethylene and C₃-C₁₀alpha-olefin units. Some or all of the above may be important forcontrolling the microstructure within the copolymer chains as well ascontrolling variations of the C₃-C₁₀ alpha-olefin unit composition fromchain to chain.

Functionalization of the Copolymer

According to one or more embodiments, the copolymer described herein maybe functionalized. The invention provides functionalized derivatives ofthe copolymers described above, and provides for compositions comprisingthe same. The functionalized copolymers of this invention may exhibitlower viscosities for better melt flows and lower operating temperaturesin various processing applications. The invention also relates tomethods of using these functionalized copolymers in applicationsrequiring particular processing elements and/or specific physicalproperties in the final product. In still another aspect, the inventionrelates to the articles prepared from these functionalized copolymers.These functionalized copolymers and polymeric blends containing thesame, may be employed in the preparation of solid articles, such asmoldings, films, sheets, and foamed objects. These articles may beprepared by molding, extruding, or other processes. The functionalizedcopolymers are useful in adhesives, tie layers, laminates, polymericblends, and other end uses. The resulting products may be used in themanufacture of components for automobiles, such as profiles, bumpers andtrim parts, or may be used in the manufacture of packaging materials,electric cable insulation, coatings and other applications.

The ethylene/C₃-C₁₀ alpha-olefin copolymers can be functionalized byincorporating at least one functional group in the copolymer structure.Exemplary functional groups may include, for example, ethylenicallyunsaturated mono- and di-functional carboxylic acids, ethylenicallyunsaturated mono- and di-functional carboxylic acid anhydrides, saltsthereof and esters thereof and epoxy-group containing esters ofunsaturated carboxylic acids. Such functional groups may be incorporatedinto the copolymer by reaction with some or all of the unsaturation inthe copolymer

Examples of the unsaturated carboxylic acids, dicarboxylic acids whichmay be present in the functionalized copolymer are those having about 3to about 20 carbon atoms per molecule such as acrylic acid, methacrylicacid, maleic acid, fumaric acid and itaconic acid. Unsaturateddicarboxylic acids having about 4 to about 10 carbon atoms per moleculeand anhydrides thereof are especially preferred. Compounds that can bereacted with the unsaturation in the copolymer include for example,maleic acid, fumaric acid, itaconic acid, citraconic acid,cyclohex-4-ene-1,2-di-carboxylic acid,bicyclo[2.21]hept-5-ene-2,3-dicarboxylic acid, maleic anhydride,itaconic anhydride, citraconic anhydride, allyl succinic anhydride,4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride andbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride. One particularlyuseful functional group may be introduced using maleic anhydride.

The ethylene/C₃-C₁₀ alpha-olefin copolymers can be functionalized by anene reaction of the alkenyl group of the copolymer and an enophilecontaining a multiple bond.

The amount of the functional group present in the functionalizedcopolymer can vary. The functional group can typically be present in anamount of at least about 0.3 weight percent, or at least 1.0 weightpercent, preferably at least about 5 weight percent, and more preferablyat least about 7 weight percent. The functional group will typically bepresent in an amount less than about 40 weight percent, preferably lessthan about 30 weight percent, and more preferably less than about 25weight percent, or less than about 10 weight percent and more preferablyless than about 5 weight percent. A desirable range can be anycombination of any lower wt % limit with any upper wt % limit describedherein provided the lower limit is less than the upper limit, each ofwhich combinations of upper and lower limits are disclosed herein.

Polymers Plasticized with the Copolymers

The ethylene/C₃-C₁₀ alpha olefin copolymers described herein are blendedwith at least one polyolefin to prepare the plasticized compositions ofthis invention.

Suitable polyolefins include homopolymers or copolymers of one or moreolefins selected from C₂ to C₂₀ linear, branched, cyclic, andaromatic-containing monomers, specifically including ethylene, 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,1-dodecene, 4-methyl-1-pentene, 3-methyl-1-pentene,3,5,5-trimethyl-1-hexene, 5-ethyl-1-nonene, vinylcyclohexane,vinylcyclohexene, vinylnorbornene, ethylidene norbornene,cyclopentadiene, cyclopentene, cyclohexene, cyclobutene,vinyladamantane, styrene, alpha-methylstyrene, para-alkylstyrenes suchas paramethyl styrene, 4-phenyl-1-butene, allyl benzene, vinyltoluenes,vinylnaphthalene, allyl benzene, and indene. For example, the polyolefinmay be poly(4-methyl-pentene-1) homopolymer, or a copolymer of4-methyl-penten-1 and another olefin.

Preferred polyolefins include polyethylene homopolymers, polypropylenehomopolymers, polybutene homopolymers, ethylene-propylene copolymers,ethylene-butene copolymers, ethylene-hexene copolymers, ethylene-octenecopolymers, propylene-butene copolymers, propylene-hexene copolymers,propylene-octene copolymers, and copolymers of one or more olefinsselected from C₂ to C₄ olefins with one or more comonomers selected fromdiolefins and oxygen-containing olefins (examples beingethylene-propylene-diene and ethylene-vinyl acetate copolymers). Thepolyolefin component may be a blend of one or more polyolefins, or ablend of polymers comprising at least 50 wt % of one or morepolyolefins.

In certain embodiments, the polyolefin is selected from the generalclass of polyolefins known as “polyethylene” (i.e., ethylenehomopolymers, ethylene copolymers, and blends thereof). These includeplastomers having a density of less than 0.91 g/cm; low densitypolyethylene having a density of more than 0.91 g/cm³ to less than 0.94g/cm³; and high density polyethylene (HDPE) having a density of 0.94g/cm³ or more. A polyethylene material comprises at least 50 mole %, or60 mol %, or at least 70 mol %, or at least 80 mol %, or at least 90 mol%, or at least 95 mol %, or 100 mole % ethylene units. Polyethylenecopolymers may be random copolymers, statistical copolymers, blockcopolymers, and blends thereof. Comonomers are preferably selected fromC₃ to C₂₀ alpha-olefins, or from C₃ to C₁₀ alpha-olefins, or from1-butene, 1-hexene, and 1-octene; and preferably are present from 0.1 to20 wt %, or from 0.5 to 10 wt %, or from 1 to 5 wt %, or from 2 to 35 wt%, or from 5 to 30 wt %, or from 15 to 25 wt %. Polyethylene copolymersmay comprise up to 50 mol % diene.

In other embodiments, the polyolefin is selected from the general classof polyolefins known as “polypropylene” (i.e., propylene homopolymers,copolymers, and blends thereof). These include isotactic polypropylene(iPP), highly isotactic polypropylene, syndiotactic polypropylene (sPP),homopolymer polypropylene (hPP, also called propylene homopolymer orhomopolypropylene), so-called random copolymer polypropylene. Apolypropylene material comprises at least 50 mol %, or 60 mol %, or atleast 70 mol %, or at least 80 mol %, or at least 90 mol %, or at least95 mol %, or 100 mol % propylene units. Polypropylene copolymers may berandom copolymers, statistical copolymers, block copolymers, impactcopolymers, and blends thereof. Comonomers are preferably selected fromethylene and C₄ to C₂₀ alpha-olefins, or from ethylene and C₄ to C₁₀alpha-olefins, or from ethylene, 1-butene, 1-hexene, and 1-octene; andpreferably are present from 0.1 to 20 wt %, or from 1 to 10 wt %, orfrom 2 to 5 wt %, or from 2 to 35 wt %, or from 5 to 30 wt %, or from 15to 25 wt %. Polypropylene copolymers may also comprise up to 50 mol %diene.

In other embodiments, the polyolefin is selected from the general classof polyolefins known as “polybutene” (i.e., butene-1 homopolymers,copolymers, and blends thereof). The homopolymer may be atactic,isotactic, or syndiotactic polybutene, and blends thereof. The copolymercan be a random copolymer, a statistical copolymer, a block copolymer,and blends thereof. Random copolymers include those where the comonomeris selected from ethylene, propylene, 1-hexene, and 1-octene. Blendsinclude impact copolymers, elastomers and plastomers, any of which maybe physical blends or in situ blends with the polybutene. Poly(I-butene)homopolymers and 1-butene/ethylene copolymers are commercially availablefrom Basell Polyolefins.

In other embodiments, the polyolefin is selected from the general classof polyolefins known as “ethylene-propylene (EP) elastomers” which arecopolymers of ethylene and propylene and optionally one or more dienemonomer(s), and also known in the art as EPM or EPDM elastomers. EPelastomers have little to no crystallinity with a heat of fusion of 20J/g or less, a density of 0.86 g/cm³ or less, an ethylene content from35 to 85 mol %, a diene content of 0 to 5 mol %, a minimum propylenecontent of 15 mol %, and a molecular weight of at least 50 kg/mol.

Suitable polyolefins may comprise up to 20 wt %, or up to 10%, or up to1 wt % diene (i.e., diolefin) monomers. Examples include alpha-omegadiene (i.e., di-vinyl) monomers such as 1,6-heptadiene, 1,7-octadiene,1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene,1,12-tridecadiene, and 1,13-tetradecadiene, as well as cyclic dienessuch as cyclopentadiene, vinylnorbornene, norbornadiene, ethylidenenorbornene, divinylbenzene, and dicyclopentadiene.

Other suitable polyolefins are described in WO 03/040201, WO 03/040095,WO 03/040202, WO 03/040233, WO 2009/020706, and WO 03/040442.

The method of making the polyolefin is not critical, as it can be madeby slurry, solution, gas phase, high pressure or other suitableprocesses, and by using catalyst systems appropriate for thepolymerization of polyethylenes, such as chromium catalysts,metallocene-type catalysts, other appropriate catalyst systems orcombinations thereof, or by free-radical polymerization. Catalystsystems suitable to make polyethylene are well known in the art; see,for example Metallocene-Based Polyolefins (Wiley & Sons, 2000).

In one or more embodiments, one or more of the ethylene/C₃-C₁₀ alphaolefin plasticizer components of the invention is present in an amountof from a low of 0.5 wt %, or 1 wt %, or 2 wt %, or 3 wt %, or 4 wt %,or 5 wt %, to a high of 50 wt %, or 45 wt %, or 40 wt %, or 35 wt %, or30 wt %, or 25 wt %, or 20 wt %, or 15 wt %, or 10 wt %, or 5 wt %,based on total weight of plasticizer component(s) and polyolefin(s),wherein a desirable range can be any combination of any lower wt % limitwith any upper wt % limit described herein provided the lower limit isless than the upper limit. In other embodiments, the compositionincludes the at least one ethylene/C₃-C₁₀ alpha olefin plasticizer in anamount of about 1 to 40 wt %, or 2 to 30 wt %, or 4 to 20 wt %, based onthe total weight of the composition.

In one or more embodiments, one or more polyolefin component is presentin an amount of from a low of 50 wt %, or 55 wt %, or 60 wt %, or 65 wt%, or 70 wt %, or 75 wt %, or 80 wt %, or 85 wt %, or 90 wt %, or 95 wt% to a high of 99 wt %, or 95 wt %, or 90 wt %, or 85 wt %, or 80 wt %,or 75 wt %, or 70 wt %, or 65 wt %, or 60 wt %, based on total weight ofethylene/C₃-C₁₀ alpha olefin plasticizer component(s) and polyolefin(s),wherein a desirable range can be any combination of any lower wt % limitwith any upper wt % limit described herein provided the lower limit isless than the upper limit. In other embodiments, the compositionincludes at least one polyolefin in an amount of about 60 to 99 wt %, or70 to 98 wt %, or 80 to 96 wt %, based on the total weight of thecomposition.

Additives commonly used in the polyolefin industry to impart certaindesirable properties may be present in the polyolefin compositions ofthe present invention. Such additives are described in Plastics AdditiveHandbook, 5^(th) Ed.; H. Zweifel, Ed. (Hanser-Gardner, 2001) and includeantioxidants (including organic phosphites, hindered amines, andphenolics), stabilizers (including UV stabilizers and other UVabsorbers), nucleating agents (including clarifying agents, metal saltssuch as sodium benzoate, sorbitol derivatives, and metal phosphates),pigments, dyes, color masterbatches, processing aids, waxes, oils,lubricants, surfactants, slip agents (including metal salts of fattyacids such as zinc stearate and fatty acid amides such erucamide),tackifiers, block, antiblock, neutralizers (such as hydro talcite), acidscavengers, anticorrosion agents, cavitating agents, blowing agents,quenchers, antistatic agents, fire retardants, cure or cross linkingagents or systems (such as elemental sulfur, organo-sulfur compounds,organic peroxides, and di- or tri-amines), coupling agents (such assilane), and combinations thereof. The additives may be present inamounts known in the art to be effective, preferably at 0.01 to 10 wt %(100 to 100,000 ppm), or 0.02 to 1 wt % (200 to 10,000 ppm), or 0.025 to0.5 wt % (250 to 5,000 ppm), or 0.05 to 0.25 wt % (500 to 2,500 ppm), or0.1 to 5 wt % (1,000 to 50,000 ppm), based upon the weight of thecomposition (where ppm is parts-per-million by weight).

Fillers may be present in the polyolefin compositions of the presentinvention. Desirable fillers include but not limited to: natural orsynthetic mineral aggregates (including talc, wollastonite, and calciumcarbonate), fibers (including glass fibers, carbon fibers, or polymericfibers), carbon black, graphite, natural and synthetic clays (includingnanoclays and organoclays), sand, glass beads, and any other porous ornonporous fillers and supports known in the art, utilized alone oradmixed to obtain desired properties. The filler may be present at 0.1to 50 wt %, or 1 to 40 wt %, or 2 to 30 wt %, or 5 to 20 wt %, based onthe weight of the total composition. Filler content is equated with thewt % ash content as determined by the ISO 3451-1 (A) test method.Blending

The ethylene/C₃-C₁₀ alpha olefin plasticizer(s), polyolefin(s), andoptional additives can be combined using any suitable means. Thoseskilled in the art will be able to determine the appropriate procedureto balance the need for intimate mixing with the desire for processeconomy. For example, one or more polyolefin component can be in theform of pellets or reactor granules, which are combined with thecopolymer plasticizer(s) and optional additives by simple physicalblending of constituent pellets and/or granules, since the forming ofarticles includes a (re)melting and mixing of the raw material(s). Thepolyolefin components may be in any physical form when blended with theethylene/C₃-C₁₀ alpha olefin plasticizer(s) and optional additives. Forexample, they may be in the form of reactor granules (i.e., granules ofpolymer that are isolated from the polymerization reactor prior to anyprocessing procedures), or in the form of pellets that are formed frommelt extrusion of the reactor granules. The polyolefin(s),ethylene/C₃-C₁₀ alpha olefin plasticizer, and optional additives can beblended by any suitable means known to those skilled in the art such as,for example, the blending processes described in WO 2009/020706.

The compositions of the present invention can be useful for thefabrication of shaped articles made or formed by any useful discretemolding or continuous extrusion means for forming and shapingpolyolefins known in the art, including: compression molding, injectionmolding, co-injection molding, gas-assisted injection molding, blowmolding, multi-layer blow molding, injection blow molding, stretch blowmolding, extrusion blow molding, transfer molding; cast molding,rotational molding, foam molding, slush molding, transfer molding, wetlay-up or contact molding, cast molding, cold forming matched-diemolding, thermoforming, vacuum forming, film blowing, film or sheetcasting, sheet extrusion, profile extrusion or co-extrusion, fiberspinning, fiber spunbonding, fiber melt blowing, lamination,calendering, coating, pultrusion, protrusion, draw reduction, foaming,or other forms of processing such as described in, for example, PlasticsProcessing (Radian Corporation, Noyes Data Corp. 1986), or combinationsthereof.

The plasticized compositions of the present invention can be useful forconsumer goods, industrial goods, construction materials, packagingmaterials, appliance components, electrical components, and automotivecomponents. Non-limiting examples of desirable articles of manufacturemade from compositions of the invention include films, tapes, sheets,fibers, tubing, pipes, hoses, belts, coatings, fabrics (woven andnonwoven), tarps, agricultural barriers, packaging (durable anddisposable), kitchen devices and household appliances (washing machines,refrigerators, blenders, air conditioners, etc.), furniture (indoor andoutdoor, such as tables, chairs, benches, shelving, etc.), sportingequipment (skis, surfboards, skateboards, skates, boots, sleds,scooters, kayaks, paddles, etc.), solid wheels, stadium seating,amusement park rides, personal protective equipment (safety helmets,shin guards, etc.), emergency response equipment, cookware, utensils,trays, pallets, carts, tanks, tubs, pond liners, storage containers(crates, pails, jars, bottles, etc.), toys, child car seats and boosterchairs, medical devices and components (including syringe parts andcatheters), luggage, tool housings (for drills, saws, etc.), wire andcable jackets, electronics housings and components (for televisions,computers, phones, hand-held devices, media players, stereos, radios,clocks, etc.), building construction materials (flooring, siding,roofing, counter tops, seals, joints, isolators, etc.), lighting,gardening equipment (handles on shovels, wheelbarrows, etc.), playgroundequipment, motor housings, pump housings, battery housings, instrumenthousings, switches, knobs, buttons, handles, pet supplies, laboratorysupplies, personal hygiene devices (razors, brushes, hairdryers, etc.),cleaning supplies (brooms, dust pans, etc.), musical instrument cases,statues, trophies, artwork, costume jewelry, picture frames, eyeglassframes, plant pots, and firearm components.

Plasticized polyolefin compositions of the present invention provide forimproved plasticization durability of the plasticizer relative tocomparable compositions made using conventional plasticizers. Improvedplasticization durability is advantageous for successful long-termproperty retention. In certain embodiments, useful plasticizedpolyolefin compositions may exhibit a reduced TGA Volatility.Plasticized polyolefin compositions of the present invention provide forlower glass transition temperatures relative to comparable compositionsmade using a conventional plasticizer. A lower Tg is advantageous forimproved low temperature flexibility and toughness. Plasticizedpolyolefin compositions of the present invention may also provide forlower melt viscosity relative to comparable compositions made using aconventional plasticizer. A lower melt viscosity (e.g., MI or MFR) isadvantageous for improved low temperature flexibility and toughness.

EXAMPLES

The following examples are illustrative, but not limiting, of themethods and compositions of the present disclosure. Examples 1-16exemplify different copolymers comprising ethylene units and propyleneunits and processes for producing them. As shown, changes in theconditions and parameters of the process, such as the feed rate ofvarious reactants, may be employed to achieve different characteristicsof the resulting copolymer such as changing the crossover temperature ofthe copolymer.

Examples F1-F12 exemplify different functionalized copolymers andprocesses for producing the same.

Table 5 below summarizes the characteristics of the copolymer fromselect examples from below.

TABLE 5 PEE + EPP + Mn Ethylene EEE EEP PEP EPE PPE PPP T_(Crossover)Vinylidene GPC MW Example (mol %) (%) (%) (%) (%) (%) (%) N_(C2) (° C.)(%) (g/mol) (g/mol) PDI 1 48.6 7.1 28.4 15.2 20.9 16.9 11.5 1.68 −73.5096.5 1159 4326 3.73 2 46.2 2.5 28.2 16.7 20.6 20.3 11.8 1.54 −77.60 96.01466 3249 2.22 3 64.9 25.4 31.7 9.9 20.6 10.3 2.2 2.60 −24.50 95.1 20857140 3.42 4 65.1 24.2 32.1 10.5 21.5 10.2 1.5 2.52 −27.00 95.6 2326 77833.35 5 64.0 21.4 33.2 10.7 21.9 11.0 1.7 2.39 −35.80 95.5 1241 3728 3.006 57.8 14.2 31.6 13.6 22.5 13.7 4.4 2.02 −72.70 95.7 3202 6516 2.03 767.8 27.5 32.8 9.1 21.0 9.0 0.6 2.72 −13.70 94.6 2838 5318 1.87(Comparative) 8 67.2 26.3 33.1 9.4 21.1 9.8 0.3 2.65 −18.50 94.6 22694933 2.17 (Comparative) 9 56.4 14.1 31.5 12.6 21.2 14.4 6.2 2.05 <−3794.9 3173 6948 2.19 10 55 22 28 9 17 12 13 2.60 −22.4 76.6 2883 59012.05 11 62 18 33 12 22 12 2 2.22 <−37 75.6 2318 4583 1.98 12 45 6 26 1720 20 12 1.62 <−37 81.2 2628 5260 2.00 13 54 12 32 12 21 15 8 1.99 <−3779.2 1673 3292 1.97 14 67 26 33 9 21 10 1 2.64 −20 83 3004 6139 2.04 1557 23 27 10 17 12 12 2.59 0.7 76.6 3000 6690 2.23 (Comparative) 16 57 2328 9 17 12 11 2.57 −17.78 76.9 2331 5536 2.38 (Comparative)

Example 1

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.127 wt % Cp₂ZrCl₂ intoluene), co-catalyst (5.0 wt % MMAO in toluene), solvent (toluene), andethylene and propylene monomers. The reactor was operated liquid-full at70 psig and agitated with a four-blade pitched-turbine impelleroperating at 220 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 0.90g/min and 0.90 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.71 g/min, 15.22g/min and 11.71 g/min, respectively. The reactor temperature wasmaintained at 65° C. as measured by a ⅛″ thermocouple located in thereactor. The production rate of polymer was measured gravimetrically as2.78 g/min.

The copolymer was found to contain 49 mol % of ethylene units using¹H-NMR. The relative number average molecular weight (M_(n)) and PDI ofthe copolymer were measured by GPC and found to be 1159 g/mol and 3.73,respectively. The weight average molecular weight (M_(w)) of thecopolymer was measured by ¹H-NMR and found to be 1038 g/mol and theolefin distribution in the copolymer as measured by ¹H-NMR was 96.5%methyl-vinylidene, 1.6% beta-vinylidene, 1.3% di-substituted (i.e. 2olefins in a single copolymer molecule) and 0.6% vinyl/allyl. Theaverage ethylene unit run length as measured by ¹³C-NMR was 1.68. Thecrossover temperature measured by oscillatory rheometry was determinedto be −73.5° C.

Example 2

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reactor was operatedcontinuously; with a continuous feed of catalyst (0.127 wt % Cp₂ZrCl₂ intoluene), co-catalyst (5.0 wt % MMAO in toluene), solvent (toluene),ethylene and propylene. The reactor was operated liquid-full at 70 psigand agitated with a four-blade pitched-turbine impeller operating at 220rpm. The catalyst and co-catalyst solutions were mixed immediatelybefore introduction to the reactor at feed rates of 0.87 g/min and 0.87g/min, respectively. The ethylene, propylene and toluene were also mixedtogether and fed to the reactor separately from the catalyst andco-catalyst solutions at feed rates of 2.78 g/min, 15.51 g/min and 10.65g/min, respectively. The reactor temperature was maintained at 68° C. asmeasured by a ⅛″ thermocouple located in the reactor. The productionrate of polymer was measured gravimetrically as 3.22 g/min.

The copolymer was found to contain 46 mol % ethylene units as measuredby ¹H-NMR. The relative number average molecular weight (M_(n)) and PDIof the copolymer, as measured by GPC were 1466 g/mol and 2.22,respectively. The weight average molecular weight (M_(w)) of thecopolymer as measured by ¹H-NMR was 780 g/mol and the olefindistribution in the copolymer measured by ¹H-NMR was 96.0%methyl-vinylidene, 1.8% beta-vinylidene, 1.3% di-substituted and 0.9%vinyl/allyl. The average ethylene unit run length measured by ¹³C-NMRwas 1.54. The crossover temperature measured by oscillatory rheometrywas determined to be −77.6° C.

Example 3

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.077 wt % Cp₂ZrCl₂ intoluene), co-catalyst (1.248 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 763psig and agitated with a four-blade pitched-turbine impeller operatingat 900 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 1.02g/min and 0.82 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.23 g/min, 3.30g/min and 9.31 g/min, respectively. The reactor temperature wasmaintained at 76° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.57g/min.

The copolymer was found to contain 65 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2085 g/mol and 3.42, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1645 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 95.1% methyl-vinylidene, 1.8% beta-vinylidene,1.3% di-substituted and 1.8% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.60. The crossover temperature measuredby oscillatory rheometry was −24.5° C.

Example 4

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.075 wt % Cp₂ZrCl₂ intoluene), co-catalyst (1.0 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 708psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 0.89g/min and 0.91 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.23 g/min, 3.59g/min and 9.36 g/min, respectively. The reactor temperature wasmaintained at 75° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.47g/min.

The copolymer was found to contain 65 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2326 g/mol and 3.35, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1824 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 95.6% methyl-vinylidene, 1.7% beta-vinylidene,1.1% di-substituted and 1.6% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.52. The crossover temperature measuredby oscillatory rheometry was −27.0° C.

Example 5

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.150 wt % Cp₂ZrCl₂ intoluene), co-catalyst (2.0 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 715psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 1.28g/min and 1.26 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.23 g/min, 2.60g/min and 9.38 g/min, respectively. The reactor temperature wasmaintained at 75° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.4g/min.

The copolymer was found to contain 64 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 1241 g/mol and 3.00, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1114 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 95.5% methyl-vinylidene, 1.9% beta-vinylidene,1.3% di-substituted and 1.4% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.39. The crossover temperature measuredby oscillatory rheometry was −35.8° C.

Example 6

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.167 wt % Cp₂ZrCl₂ intoluene), co-catalyst (2.222 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 696psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 0.66g/min and 0.65 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 3.09 g/min, 8.11g/min and 3.10 g/min, respectively. The reactor temperature wasmaintained at 80° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 6.63g/min.

The copolymer was found to contain 58 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 3202 g/mol and 2.03, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1310 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 95.7% methyl-vinylidene, 1.5% beta-vinylidene,1.6% di-substituted and 1.2% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.02. The crossover temperature measuredby oscillatory rheometry was approximately −72.7° C.

Example 7 (Comparative)

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.165 wt % Cp₂ZrCl₂ intoluene), co-catalyst (2.2 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 703psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 1.21g/min and 1.20 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.23 g/min, 2.51g/min and 8.50 g/min, respectively. The reactor temperature wasmaintained at 75° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.48g/min.

The copolymer was found to contain 68 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2838 g/mol and 1.87, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1203 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 94.6% methyl-vinylidene, 2.1% beta-vinylidene,1.3% di-substituted and 2.0% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.72. The crossover temperature measuredby oscillatory rheometry was approximately −13.7° C.

Example 8 (Comparative)

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.182 wt % Cp₂ZrCl₂ intoluene), co-catalyst (2.42 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 704psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 1.15g/min and 1.14 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 2.20 g/min, 2.40g/min and 7.97 g/min, respectively. The reactor temperature wasmaintained at 75° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.53g/min.

The copolymer was found to contain 67 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2269 g/mol and 2.17, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1167 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 94.6% methyl-vinylidene, 2.2% beta-vinylidene,1.3% di-substituted and 1.9% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.65. The crossover temperature measuredby oscillatory rheometry was approximately −18.5° C.

Example 9

A 300 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst and co-catalyst. The reaction was operatedcontinuously; with continuous feed of catalyst (0.167 wt % Cp₂ZrCl₂ intoluene), co-catalyst (2.222 wt % MMAO in toluene), solvent (toluene),ethylene, and propylene. The reactor was operated liquid-full at 701psig and agitated with a four-blade pitched-turbine impeller operatingat 1,000 rpm. The catalyst and co-catalyst solutions were mixedimmediately before introduction to the reactor at feed rates of 0.78g/min and 0.89 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst and co-catalyst solutions at feed rates of 3.34 g/min, 7.77g/min and 3.20 g/min, respectively. The reactor temperature wasmaintained at 89° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 7.98g/min.

The copolymer was found to contain 56 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 3173 g/mol and 6948, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1281 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 94.9% methyl-vinylidene, 2.0% beta-vinylidene,1.8% di-substituted and 1.3% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.05. The crossover temperature measuredby oscillatory rheometry was lower than −37° C.

Example 10

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.011 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.023 wt % FAB in toluene), scavenger(0.0080 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1520 psig andagitated with a four-blade pitched-turbine impeller operating at 1041rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.31,0.32 and 0.52 g/min, respectively. The ethylene, propylene and toluenewere also mixed together and fed to the reactor separately from thecatalyst, co-catalyst and scavenger solutions at feed rates of 0.60,2.98 and 6.31 g/min, respectively. The reactor temperature wasmaintained at 134° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 0.96g/min.

The copolymer was found to contain 55 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2883 g/mol and 2.05, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1411 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 76.6% methyl-vinylidene, 14.1% beta-vinylidene,7.2% di-substituted and 2.1% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.60. The crossover temperature measuredby oscillatory rheometry was approximately −22.4° C.

Example 11

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.141 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.144 wt % FAB in toluene), scavenger(0.032 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1553 psig andagitated with a four-blade pitched-turbine impeller operating at 1,000rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.22g/min, 0.49 g/min and 0.25 g/min, respectively. The ethylene, propyleneand toluene were also mixed together and fed to the reactor separatelyfrom the catalyst, co-catalyst and scavenger solutions at feed rates of1.75 g/min, 2.55 g/min and 7.04 g/min, respectively. The reactortemperature was maintained at 120° C. as measured by a ⅛″ thermocouplein the reactor. The production rate of copolymer was measuredgravimetrically as 2.53 g/min.

The copolymer was found to contain 62 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2318 g/mol and 1.98, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1199 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 75.6% methyl-vinylidene, 16.8% beta-vinylidene,6.3% di-substituted and 1.4% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.22. The crossover temperature measuredby oscillatory rheometry was lower than −37° C.

Example 12

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.04 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.083 wt % FAB in toluene), scavenger(0.005 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1533 psig andagitated with a four-blade pitched-turbine impeller operating at 1,000rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.32g/min, 0.34 g/min and 0.33 g/min, respectively. The ethylene, propyleneand toluene were also mixed together and fed to the reactor separatelyfrom the catalyst, co-catalyst and scavenger solutions at feed rates of1.60 g/min, 3.05 g/min and 3.68 g/min, respectively. The reactortemperature was maintained at 98° C. as measured by a ⅛″ thermocouple inthe reactor. The production rate of copolymer was measuredgravimetrically as 3.69 g/min.

The copolymer was found to contain 45 mol % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2628 g/mol and 2.00, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1410 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 81.2% methyl-vinylidene, 13.0% beta-vinylidene,5.2% di-substituted and 0.6% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 1.62. The crossover temperature measuredby oscillatory rheometry was lower than −37° C.

Example 13

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.04 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.082 wt % FAB in toluene), scavenger(0.01 wt % TEAL in toluene), solvent (toluene), ethylene, and propylene.The reactor was operated liquid-full at 1533 psig and agitated with afour-blade pitched-turbine impeller operating at 1019 rpm. The catalyst,co-catalyst and scavenger solutions were mixed immediately beforeintroduction to the reactor at feed rates of 0.52 g/min, 0.52 g/min and0.37 g/min, respectively. The ethylene, propylene and toluene were alsomixed together and fed to the reactor separately from the catalyst,co-catalyst and scavenger solutions at feed rates of 1.78 g/min, 2.76g/min and 3.98 g/min, respectively. The reactor temperature wasmaintained at 119° C. as measured by a ⅛″ thermocouple in the reactor.The production rate of copolymer was measured gravimetrically as 3.5g/min. The copolymer was found to contain 54 mol. % ethylene as measuredby ¹H-NMR. The relative number average molecular weight (Mn) and PDI ofthe copolymer, as measured by GPC were 1673 g/mol and 1.97,respectively. The weight average molecular weight (Mw) of the copolymeras measured by ¹H-NMR was 913 g/mol and the olefin distribution in thecopolymer measured by ¹H-NMR was 79.2% methyl-vinylidene, 14.7%beta-vinylidene, 5.0% di-substituted and 1.1% vinyl/allyl. The averageethylene unit run length measured by ¹³C-NMR was 1.99. The crossovertemperature measured by oscillatory rheometry was lower than −37° C.

Example 14

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.093 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.191 wt % FAB in toluene), scavenger(0.011 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1462 psig andagitated with a four-blade pitched-turbine impeller operating at 1,000rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.65g/min, 0.68 g/min and 0.63 g/min, respectively. The ethylene, propyleneand toluene were also mixed together and fed to the reactor separatelyfrom the catalyst, co-catalyst and scavenger solutions at feed rates of1.70 g/min, 2.20 g/min and 6.85 g/min, respectively. The reactortemperature was maintained at 105° C. as measured by a ⅛″ thermocouplein the reactor. The production rate of copolymer was measuredgravimetrically as 2.63 g/min.

The copolymer was found to contain 67 mol. % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 3004 g/mol and 2.04, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1504 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 83.0% methyl-vinylidene, 11.0% beta-vinylidene,5.0% di-substituted and 2.0% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.64. The crossover temperature measuredby oscillatory rheometry was approximately −20.0° C.

Example 15 (Comparative)

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.008 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.015 wt % FAB in toluene), scavenger(0.011 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1549 psig andagitated with a four-blade pitched-turbine impeller operating at 1008rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.37g/min, 0.40 g/min and 0.27 g/min, respectively. The ethylene, propyleneand toluene were also mixed together and fed to the reactor separatelyfrom the catalyst, co-catalyst and scavenger solutions at feed rates of0.48 g/min, 3.0 g/min and 6.98 g/min, respectively. The reactortemperature was maintained at 140° C. as measured by a ⅛″ thermocouplein the reactor. The production rate of copolymer was measuredgravimetrically as 0.61 g/min.

The copolymer was found to contain 57 mol. % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 3,000 g/mol and 2.23, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1505 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 76.6% methyl-vinylidene, 13.7% beta-vinylidene,7.6% di-substituted and 2.1% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.59. The crossover temperature measuredby oscillatory rheometry was approximately 0.7° C.

Example 16 (Comparative)

A 100 mL Parr reactor was equipped with a water jacket for temperaturecontrol, a nitrogen-purged receiver for pressure control, a metered feedof ethylene gas and high-pressure metering pumps for separate feeds ofpropylene, toluene, catalyst, co-catalyst and scavenger. The reactionwas operated continuously; with continuous feed of catalyst (0.015 wt %Cp₂ZrMe₂ in toluene), co-catalyst (0.031 wt % FAB in toluene), scavenger(0.009 wt % TEAL in toluene), solvent (toluene), ethylene, andpropylene. The reactor was operated liquid-full at 1539 psig andagitated with a four-blade pitched-turbine impeller operating at 1001rpm. The catalyst, co-catalyst and scavenger solutions were mixedimmediately before introduction to the reactor at feed rates of 0.26g/min, 0.26 g/min and 0.46 g/min, respectively. The ethylene, propyleneand toluene were also mixed together and fed to the reactor separatelyfrom the catalyst, co-catalyst and scavenger solutions at feed rates of0.52 g/min, 3.04 g/min and 6.62 g/min, respectively. The reactortemperature was maintained at 140° C. as measured by a ⅛″ thermocouplein the reactor. The production rate of copolymer was measuredgravimetrically as 0.64 g/min.

The copolymer was found to contain 57 mol. % ethylene as measured by¹H-NMR. The relative number average molecular weight (Mn) and PDI of thecopolymer, as measured by GPC were 2331 g/mol and 2.38, respectively.The weight average molecular weight (Mw) of the copolymer as measured by¹H-NMR was 1197 g/mol and the olefin distribution in the copolymermeasured by ¹H-NMR was 76.9% methyl-vinylidene, 14.4% beta-vinylidene,6.9% di-substituted and 1.8% vinyl/allyl. The average ethylene unit runlength measured by ¹³C-NMR was 2.57. The crossover temperature measuredby oscillatory rheometry was approximately −17.8° C.

Examples and Comparative Examples for Ethylene Alpha Olefin CopolymerFunctionalization Example F1

Ethylene propylene copolymer (Example 1) 168.5 g (0.16 mol) and maleicanhydride 23.5 g (0.24 mol) were charged to a 350 mL PARR pressurereactor equipped with a stirrer and a thermocouple. The reaction mixturewas heated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo. Analytical analysis: acid number: 0.966 and 91.0%functionalized copolymer.

Example F2

Ethylene propylene copolymer (Example 2) 150 g (0.19 mol) and maleicanhydride 28.3 g (0.29 mol) were charged to a 350 mL PARR pressurereactor equipped with a stirrer and a thermocouple. The reaction mixturewas heated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo. Analytical analysis: acid number: 1.24 and 91.6%functionalized copolymer.

Example F3

Ethylene propylene copolymer (Example 3) 822.5 g (0.5 mol) and maleicanhydride 73.55 g (0.75 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 2 L round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo affording 827.5 g of product. Analytical analysis: acid number:0.577 and 85.4% functionalized copolymer.

Example F4

Ethylene propylene copolymer (Example 4) 900 g (0.49 mol) and maleicanhydride 72.65 g (0.74 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 2 L round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo affording 901.4 g of product. Analytical analysis: acid number:0.571 and 84.8% functionalized copolymer.

Example F5

Ethylene propylene copolymer (Example 5) 781 g (0.7 mol) and maleicanhydride 103.1 g (1.05 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 1 L round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo affording 846.5 g of product. Analytical analysis: acid number:0.986, and 88.6% functionalized copolymer.

Example F6

Ethylene propylene copolymer (Example 6 1,000 g (0.76 mol) and maleicanhydride 112.3 g (1.15 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 2 L round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo affording 1076.8 g of product. Analytical analysis: acidnumber: 0.76, and 78% functionalized copolymer.

Example F7 (Comparative)

Ethylene propylene copolymer (Example 7) 450 g (0.374 mol), ethylenepropylene copolymer (Example 8) 450 g (0.386 mol) and maleic anhydride111.79 g (1.14 mol) were charged to a 2 L PARR pressure reactor equippedwith a stirrer and a thermocouple. The reaction mixture was heated to50° C., purged with nitrogen for 15 min with stirring. The reactortemperature was raised to 235° C. and maintained at that temperature for6 h while stirring. The reaction mixture was then cooled to 90° C. andtransferred to a 2 L round bottom flask. The reaction mixture was thenheated and the unreacted maleic anhydride was removed in vacuo affording960.2 g of product. Analytical analysis: acid number: 0.923, and 87.0%functionalized copolymer.

Example F8

Ethylene propylene copolymer (Example 9) 845.2 g (0.66 mol) and maleicanhydride 97.0 g (0.99 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 2 L 3N-round bottom flask. The reactionmixture was then heated and the unreacted maleic anhydride was removedin vacuo affording 904.2 g of product. Analytical analysis: acid number:0.858, and 82.2% functionalized copolymer.

Example F9

Ethylene propylene copolymer (Example 10) 150.0 g (0.11 mol) and maleicanhydride 15.7 g (0.159 mol) were charged to a 35 0 mL PARR pressurereactor equipped with a stirrer and a thermocouple. The reaction mixturewas heated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL 3N-round bottom flask. Thereaction mixture was then heated and the unreacted maleic anhydride wasremoved in vacuo affording 155.3 g of product. Analytical analysis: acidnumber: 0.72, and 85.6% functionalized copolymer.

Example F10

Ethylene propylene copolymer (Example 11) 150.0 g (0.125 mol) and maleicanhydride 18.4 g (0.19 mol) were charged to a 350 mL PARR pressurereactor equipped with a stirrer and a thermocouple. The reaction mixturewas heated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL 3N-round bottom flask. Thereaction mixture was then heated and the unreacted maleic anhydride wasremoved in vacuo affording 159.5 g of product. Analytical analysis: acidnumber: 0.78, and 81.3% functionalized copolymer

Example F11

Ethylene propylene copolymer (Example 12) 150.0 g (0.11 mol) and maleicanhydride 15.7 g (0.160 mol) were charged to a 350 mL PARR pressurereactor equipped with a stirrer and a thermocouple. The reaction mixturewas heated to 50° C., purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL 3N-round bottom flask. Thereaction mixture was then heated and the unreacted maleic anhydride wasremoved in vacuo affording 155.6 g of product. Analytical analysis: acidnumber: 0.685, and 85.3% functionalized copolymer.

Example F12

Ethylene propylene copolymer (Example 13) 1,000 g (1.1 mol) and maleicanhydride 161.2 g (1.64 mol) were charged to a 2 L PARR pressure reactorequipped with a stirrer and a thermocouple. The reaction mixture washeated to 50 C, purged with nitrogen for 15 min with stirring. Thereactor temperature was raised to 235° C. and maintained at thattemperature for 6 h while stirring. The reaction mixture was then cooledto 90° C. and transferred to a 500 mL 3N-round bottom flask. Thereaction mixture was then heated and the unreacted maleic anhydride wasremoved in vacuo affording 1108.5 g of product. Analytical analysis:acid number: 1.057, and 83.8% functionalized copolymer

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of the present invention.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of”. “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

When the word “about” is used herein in reference to a number, it shouldbe understood that still another embodiment of the invention includesthat number not modified by the presence of the word “about.”

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

What is claimed is:
 1. A copolymer comprising ethylene units andpropylene units, wherein the copolymer has a number average molecularweight of less than 4,000 g/mol as measured by GPC; wherein the ethylenecontent of the copolymer is less than 70 mol %; at least 70% ofmolecules of the copolymer have an unsaturated group, and at least 70%of said unsaturated groups are located in a terminal vinylidene group ora tri-substituted isomer of a terminal vinylidene group; wherein thecopolymer has an average ethylene unit run length (n_(C2)) which is 2.64or less, as determined by ¹³C NMR spectroscopy, and satisfies therelationship shown by the expression below:$n_{C\; 2} < \frac{\left( {{EEE} + {EEA} + {AEA}} \right)}{\left( {{AEA} + {0.5{EEA}}} \right)}$whereinEEE = (x_(C 2))³, EEA = 2(x_(C 2))²(1 − x_(C 2)), AEA = x_(C 2)(1 − x_(C 2))²,x_(C2) being the mole fraction of ethylene incorporated in the polymeras measured by ¹H-NMR spectroscopy, E representing an ethylene unit, andA representing propylene unit.
 2. The copolymer of claim 1, wherein thecopolymer has a crossover temperature of −20° C. or lower.
 3. Thecopolymer of claim 1, wherein the copolymer has an average ethylene unitrun length of less than 2.6.
 4. The copolymer of claim 1, wherein theethylene content of the copolymer is less than 55 mol %.
 5. Thecopolymer of claim 1, wherein the ethylene content of the copolymer isat least 30 mol % and less than 65 mol %.
 6. The copolymer of claim 1,wherein the ethylene content of the copolymer is at least 40 mol % andless than 60 mol %.
 7. The copolymer of claim 1, wherein the propylenecontent of the copolymer is at least 40 mol %.
 8. The copolymer of claim1, wherein at least 85 mol % of the copolymer terminates in the terminalvinylidene group or the tri-substituted isomer of the terminalvinylidene group.
 9. The copolymer of claim 1, wherein the copolymer hasan average ethylene unit run length of less than 2.4.
 10. The copolymerof claim 1, wherein the copolymer has an average ethylene unit runlength of less than
 2. 11. The copolymer of claim 1, wherein thecrossover temperature of the copolymer is −35° C. or lower.
 12. Thecopolymer of claim 1, wherein the crossover temperature of the copolymeris −40° C. or lower.
 13. The copolymer of claim 1, wherein the copolymerhas a polydispersity index of less than or equal to
 4. 14. The copolymerof claim 1, wherein the copolymer has a polydispersity index of lessthan or equal to
 3. 15. The copolymer of claim 1, wherein the numberaverage molecular weight of the copolymer is between 800 and 3,000g/mol, as measured by GPC.
 16. The copolymer of claim 1, wherein lessthan 20% of unit triads in the copolymer are ethylene-ethylene-ethylenetriads.
 17. The copolymer of claim 1, wherein the copolymer has a numberaverage molecular weight of less than 2,000 g/mol, as measured by GPC.18. The copolymer of claim 17, wherein the ethylene content of thecopolymer is at least 40 mol % and less than 60 mol %.
 19. The copolymerof claim 18, wherein the copolymer has a polydispersity index of lessthan or equal to
 4. 20. The copolymer of claim 19, wherein the crossovertemperature of the copolymer is −35° C. or lower.
 21. The copolymer ofclaim 20, wherein less than 20% of unit triads in the copolymer areethylene-ethylene-ethylene triads.
 22. The copolymer of claim 21,wherein the crossover temperature of the copolymer is −40° C. or lower.